An agricultural baler is a trailed machine (PTM—pulled type machine) used in agriculture for the purpose of creating bales of (typically) straw or other biomass such as hay, silage or similar crop material produced during a harvesting or mowing operation.
Knotters are used for binding bales of harvested crop material or other substances, so that bales may be handled, stored or otherwise manipulated without breaking apart. Knotters are therefore used to tie at least one and typically several strands of binding material such as twine or any other suitable type of lineal object around the bales, and to bind it in a manner that leads to a satisfactory knot. These knotters have a knotting system with at least one movable part. The movable part can e.g. be the needles and/or needle yokes. More detailed descriptions of knotters are found in U.S. Pat. No. 4,142,746, EP2108247, EP0426905. In essence the movable part is used to arrange the lineal object around the bale at the moment the bale has reached a predetermined desired length. This movement is arranged by a driver, operatively connected to the at least one movable part. The driver for example has a control means (e.g. a trip mechanism), controlling the operations of the knotting system by allowing the moving of the one or more movable parts of the knotting system when the bale reaches a desired length for binding by the knotting system.
It is clear that moving parts in a machine are always dangerous for operators, for example when such operators come near to those moving parts for maintenance, especially when the movement of such parts is not continuous but is conditional, as in the case of a knotter where the binding only starts when the bale has a predetermined desired length. In general such knotters may have no or insufficient coverage of their moving parts. Even in realizations with covers (even when such covers are manually locked), as for example in DD112320, the safety problem remains when the operator opens such cover and approaches the moving parts for maintenance work. In particular in the system described in DD112320, means are provided for preventing an operator to open a cover while the needles are present in the baling chamber; however, nothing prevents the operator to open the cover before the bale has reached its predetermined length, after which the needles can still move into the baling chamber, thus potentially hurting or injuring the operator.
The need for increasing operator safety is addressed in standardization efforts by emphasizing better coverage of moving parts in the knotter area.
Hence there is room for good knotter devices, for example balers provided with such knotter devices, showing improved operator safety.